Question

A researcher studying the nutritional value of a new candy places a 6.50 g sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. If the heat capacity of the calorimeter is 34.50 kJ.K-, how many nutritional Calories are there per gram of the candy?

A. 2.8 kcal/g
B. 4.7 kcal/g
C. 6.3 kcal/g
D. 8.2 kcal/g

Answer 1

Bomb calorimetry is used to determine the nutritional value of food. To find the nutritional Calories per gram of the candy, the heat released per gram of candy is calculated and converted to kilocalories (kcal). The answer is approximately 8.2 kcal/g.

Step-by-step explanation:

Bomb calorimetry is a technique used to determine the nutritional value of food by measuring the heat released when it is burned. In this case, a 6.50 g sample of the candy is burned in a bomb calorimeter with a heat capacity of 34.50 kJ.K-. To find the nutritional Calories per gram of the candy, we need to calculate the heat released per gram of candy and convert it to kilocalories (kcal).

First, we calculate the heat released by multiplying the mass of the candy sample (6.50 g) by the heat capacity of the calorimeter (34.50 kJ.K-):

Heat released = 6.50 g x 34.50 kJ.K- = 224.25 kJ

To convert this heat value to kilocalories, we divide by 4.18 since 1 kilocalorie is equal to 4.18 kilojoules:

Heat released in kcal = 224.25 kJ / 4.18 = 53.67 kcal

Finally, we divide the heat released in kilocalories by the mass of the candy sample to find the nutritional Calories per gram:

Calories per gram = 53.67 kcal / 6.50 g ≈ 8.26 kcal/g

Therefore, the correct answer is D. 8.2 kcal/g.